Fork lift truck having a lifting device mounted for pivotal movement about a vertical pivotal axle



Sheet 1 y 1969 K. STEINERT FORK LIFT TRUCK HAVING A LIFTING DEVICEMOUNTED F'C'R PIVOTAL MOVEMENT ABOUT A VERTICAL PIVOTAL AXLE Filed May5. 1966 Fig. 1

. Sheet 2 May 20, 1969 K. STEINERT FORK LIFT TRUCK HAVING A LIFTINGDEVICE MOUNTED FOR PI OTAL MOVEMENT ABOUT A VERTICAL PIVOTAL AXLE FlledMay 5, 1966 May 20, 1969 K. STEINERT 3,445,019

FORK LIFT TRUCK HAVING A LIFTING DEVICE MOUNTED FOR PIVOTAL "OVEMENTABOUT A VERTICAL PIVOTAL AXLE Filed May 5. 1966 Sheet 3 of 4 May 20,1969- K. s'r mER'r 3,445,019

FORK LIFT TRUCK HAVING 'A LIFTING DEVICE MOUNTED FOR PIVOTAL MOVEMENTABOUT A VERTICAL PIVO'IAL AXLE Filed lay 5. 1966 Sheet & of 4 UnitedStates Patent 3,445,019 FORK LIFT TRUCK HAVING A LIFTING DEVICE MOUNTEDFOR PIVOTAL MOVEMENT ABOUT A VERTICAL PIVOTAL AXLE Kurt Steinert,Herzogenaurach, Germany, assignor to Karl Heinz Schmidt, Vorra, KreisHersbruck, Germany Filed May 5, 1966, Ser. No. 547,864 Claims priority,application Germany, May 20, 1965, Sch 37,099 Int. Cl. B66f 9/10 US. Cl.214671 2 Claims ABSTRACT OF THE DISCLOSURE A fork lift truck capable ofboth front and side operations in which the vehicle is C-shaped in itsground plan and the lifting means is slewable about a vertical pivotalaxle arranged at or adjacent an inner corner of the vehicle. The liftingmeans is linked with the vertical pivotal axle via an outrigger allowinghorizontal displacement of the lifting means relative to the pivotalaxle.

This invention relates to vehicles for handling materials and moreparticularly to fork lift trucks.

Fork lift trucks are constructed as front fork lift trucks as well asside fork lift trucks, and in view of the limited possibility ofemploying each of both types of fork lift trucks, there have heretoforebeen constructed so-called universal lift trucks which are intended topermit a front operation as well as a side operation.

A known structural type of such universal lift trucks virtuallyconstitutes nothing more than a front lift truck, the lifting device ofwhich can be pivoted about a vertical pivotal axle. While it is truethat in this manner it is possible that the load which can be lifted andlowered in a front operation is now put down laterally upon the platformof the lift truck, but a proper side operation is neverthelessimpossible with this known vehicle.

Another known structural type of such a so-called universal lift truckvirtually constitutes nothing more than a lateral lift truck, thetravelling gear of which permits a travel also transversely of thenormal direction of travel.

This lift truck is disadvantageous due to the great breadth of thevehicle at the front operation-i.e., when the vehicle is travellingtransversely. Pivoting the load with respect to the vehicle isimpossible with this type of lift truck.

The object of this invention is to provide a fork lift truck which canbe employed for front service as well as for a genuine side service, andwhich moreover permits the load to be put down onto the vehicleplatform, and which also permits alternate operation, i.e., a frontsidelifting and a sidewise lowering of the load and vice-versa,respectively.

Accordingly, the invention originates from a fork lift truck having alifting device mounted for pivotal movement about a vertical pivotalaxle, and the present fork lift truck is characterized in that suchpivotal axle is arranged at or adjacent an inner corner of theside-recess of the vehicle which, in its ground plan, is C-shaped in amanner known per se, and in that the lifting device is linked with suchpivotal axle by means of a cantilever arm, for example, lazy tongs,permitting a horizontal displacement of the lifting device also knownper se.

According to a further feature of the invention, on the free end of thehorizontally extensible cantilever arm or outrigger there is mounted aframe in which the lifting mast underpart guiding the vertically movablelifting mast extension together with the lifting slide which also isvertically movable therein, for its part is, again vertically "icemovable and moreover optionally laterally movable in such a manner thatthe lower edge of the lifting mast underpart can be lowered from anormal position substantially directly above the plane of the lift truckplatform into a lowermost position substantially touching the path oftravel or roadway. According to a modified structural embodiment of thepresent fork lift truck, the lifting mast extension is extensible from anormal position upwardly as well as downwardly with respect to thelifting mast underpart guiding the lifting mast extension and optionallylaterally movably mounted on the free end of the horizontally extensibleoutrigger, with such normal position being determined by the lower edgeof the lifting mast underpart, and which lower edge is disposedsubstantially directly above the plane of the platform of the lifttruck.

The horizontally extensible outrigger is preferably extensible so farthat it is swingable also when the parts of the lifting device arelowered beneath the plane of the platform of the vehicle. The outercorner of the vehicle that lies in the pivotal range of the horizontallyextensible outrigger holding the lifting device may be flattened orrounded-off in its ground plan.

The pivotal movements and/or the horizontal extension of the outriggertakes place preferably by virtue of a drive by fluid under pressure andan interlocking device, e.g., a cam plate, cooperating with feelermembers of the horizontal outrigger can be provided on the verticalpivotal axis to prevent any components of the lifting device from beinglowered underneath the plane of the platform of the lift truck so longas the lifting device is within the range of the ground plan of thevehicle.

The invention will now be described in detail by way of example withreference to the attached drawings showing a preferred exemplaryembodiment of a fork lift truck according to the invention in whichFIGURE 1 is a ground plan of the fork lift truck according to theinvention in the side operative position;

FIGURE 2 is a ground plan of the fork lift truck of FIGURE 1, now in thefront operative position;

FIGURE 3 is a front view of the fork lift truck of FIGURES 1 and 2 inthe side operative position, and

FIGURE 4 is a side View of the fork lift truck of FIGURES 1 and 3 in thefront operative position.

A vehicle body 1, which substantially includes the travelling gear, thevehicle frame and the vehicle platform, of the present fork lift truckis, in its ground plan, similar to the ground plan of a known laterallift truck, i.e., the ground plan of the vehicle is substantiallyC-shaped, whereby in the vehicle is formed a side-recess 2 receiving thelifting device of the fork lift truck during side operation.

A vertical pivotal axle 3 known per se for the lifting device isarranged at or adjacent to an inner corner of the side-recess 2. In thepreferred embodiment as shown in the drawings, the vertical pivotal axle3 is located at the inner corner of the side-recess 2 of the lift truck,namely at a corner adjacent to the drivers cab indicated at 4 andarranged at the front side of the vehicle. The forward direction oftravel is indicated by an arrow A in FIG- URES l, 2 and 4. In largervehicles it is possible to arrange the engine of the vehicle as acab-over drive, while the drivers cab will be arranged at the rear sideof the vehicle. In such a case, the vertical pivotal axle 3 ispreferably arranged again at the forward comer of the recess but at theforward corner opposite the drivers cab so that the driver can observethe work of the lift truck fork also during side operation.

The vertical pivotal axle 3 constitutes the slewing journal for anoutrigger 5 which is extensible in the radial direction and which isrepresented as lazy tongs 5 mounted on the supporting member 5 journaledon the axle 3 within the scope of the embodiment shown in the drawings.At its free end, this horizontally extensible outrigger 5 carries alifting device 6 which, in turn, consists in a manner known per sesubstantially of a lifting mast underpart, a lifting mast extensionvertically movably guided in the underpart, and a lifting slide orcarriage which again is vertically movable in the extension and whichholds a lift fork 7.

A frame 8 is secured to the free end of the outrigger 5 and supports alifting mast underpart for guiding the vertically movable lifting mastextension (not illustrated) together with a lifting carriage 9vertically movable in the lifting mast extension. The arrangement issuch that the lower edge of the lifting mast underpart 10 can be loweredfrom a normal position located substantially directly above a plane ofthe lift truck platform 11 into a lowermost position substantiallytouching the roadway. As can best be seen in FIGS. 3 and 4, the axle 3and the slewable supporting member 5" both extend upwardly above thetruck platform so as to assure free pivotal movement of the liftingmechanism when the lift fork 7 is elevated above the height of theplatform.

According to another, simpler embodiment (not shown in the drawings),the lifting mast extension is extensible from a normal position upwardlyas well as downwardly with respect to the lifting mast underpart 10guiding the extension and secured to the free end of the horizontallyextensible outrigger 5, with the normal position being determined by thelower edge of the lifting mast underpart 10, and which lower edge islocated substantially directly above the plane of the platform of thelift truck.

In both embodiments, the lifting mast underpart 10 can optionally belaterally movably guided in the frame 8 arranged at the free end of thehorizontally extensible outrigger 5.

Both the slewing movement and the horizontal extension of the outrigger5 are effected preferably by virtue of a fluid pressure drive which isknown per se and hence not indicated in the drawings. The same appliesalso to the adjustment in height of the lifting rnast underpart 10insofar as the same is vertically adjustable with respect to the frame 8according to a preferred embodiment of the invention. The adjustment inheight of the lifting mast extension relative to the lifting mastunderpart 10 is effected also in a manner known per se by virtue of afluid pressure drive, while the adjustment in height of the liftingcarriage 9 relative to the lifting mast extension can be suitableeffected also in a manner known per se by a chain drive.

According to a further aspect of this invention which, however, is notshown in the drawings for claritys sake, an interlocking device such as,e.g., a cam plate, can be arranged on the vertical pivotal axle 3, andwhich interlocking device cooperates with feeler members of thehorizontal outrigger 5 and prevents any parts of the lifting device 6from being lowered underneath the plane of the platform 11 so long asthe lifting device is within the range of the ground plan of the vehicle1.

In FIGURES 1 and 3, the outrigger 5 and the lifting device 6 are shownin a pivoted position in which the fork lift truck operates as a sidefork lift truck, with the outrigger 5 in both figures being representedby full lines in the retracted position, and by dot-dash lines in itsextended position. Such a horizontal displacement of the lifting device6 is known per se and generally used in side lift trucks. The liftingcarriage 9 together with the lift fork 7 is indicated in FIGURE 3 byfull lines in a position in which the lift fork 7 is locatedsubstantially directly above the lift truck platform 11. The loweredposition of the lifting mast underpart 10, and in which the lift fork islocated directly on the roadway is indi cated in FIGURE 3 bydot-and-dash lines for the retracted position of the outrigger 5 and thedouble-dotand-dash lines for the extended position of the outrigger.

In FIGURES 2 and 4, the outrigger 5 and the lifting device 6 of the lifttruck are illustrated in a position in which the lift truck operates asa front lift truck, with both figures again showing the retractedposition of the outrigger 5 by full lines, while the extended positionis indicated by dot-dash lines. The lift fork 7 is represented by fulllines in FIGURE 4 in a position in which the fork is located directlyabove the plane of the platform 11 of the lift truck. The lifting mastunderpart is shown by dot-dash lines in FIGURE 4 in its loweredposition, in which the lift fork 7 rests on the roadway. When theoutrigger mechanism 5 is extended to the position shown in FIGURE 4, thepresent lift truck can operate as a normal front lift truck.

Apart from the above described normal operative positions, there arealso further possibilities for the lift truck. Thus, for example, in theoperative position shown in FIGURES 2 and 4, it is possible to put thelift fork 7 down onto the platform 11 by retracting the outriggermechanism 5, which feature is certainly an advantage when the load is tobe transported longer distances. This also is advantageously madepossible by the mounting of the axle 3 and the entire outriggermechanism above the upper surface of the truck platform 11 as shown inFIGS. 2 and 4.

However, insofar as the load projects at either side over the lift fork7, the load can be put directly onto the platform 11 by a correspondinglowering of the lift fork 7 when the outrigger 5 is pivoted about thevertical pivotal axle 3 into the position shown in FIGURES 1 and 3. Inthis manner, the transition from the frontal operative position into thelateral operative position is simultaneously accomplished andconsequently the load can, if desired, be lifted from the platform 11 byagain lifting the lift fork 7, while the load can be put down in amanner known per se laterally of the lift truck. A transition from theside operation into the front operation is possible just the same.Moreover, due to the interlocking means which is provided according tothe invention and which has briefly been described hereinbefore, acollision during the transition from the side into the front operationor vice-versa is out of the question because the lifting mast underpart10 and the fork 7 must always be lifted initially so far that they willbe located above the plane of the platform 11 before a slewing movementof the outrigger 5 can be performed.

According to a modified embodiment of the invention, the horizontallyextensible outrigger 5 can be extensible so far that the same will stillbe slewable when the lifting mast underpart 10 is lowered underneath theplane of the platform 11 of the vehicle. In order to facilitate thismode of operation, according to a further aspect shown at 12 in FIGURES1 and 2, it is possible that the outer corner of the vehicle lyingwithin the pivotal range of the horizontally extensible outrigger 5holding the lifting device 6 can be flattened or roundedoff in itsground plan.

Finally, the present fork lift truck can have' its operative sidesprovided with automatically extensible supporting legs known per sewhich are preferably actuated by a fluid under pressure and whichsupport the vehicle toward the roadway when the lifting fork 7 islifted.

In comparison with the above-mentioned known fork lift trucks, thepresent fork lift truck has the advantage that the lift truck requires asmall gangway breadth only, which is determined by the breadth of thevehicle, for the front operation as well as the side operation.Furthermore for the purpose of travelling greater transporting paths,this lift truck during front service permits the load to be put backinto the range within its wheel base, which can be effected by simplyretracting the outrigger 5 from its front working position, as well asby pivoting the same into the side working position. Moreover, atransition from the front operation into the side operation is possiblewithout the necessity of turning the vehicle. Due to the arrangement ofthe present vertical pivotal axle so as to be adjacent an inner cornerof the side-recess of the vehicle, it is possible that the center ofgravity of the load can be maneuvered within the region of the wheelbase and, relative to the transverse direction of the vehicle,substantially centrally, whatever the type of transport.

This invention is not to be confined to any strict conformity to theshowings in the drawings but changes or modifications may he madetherein so long as such changes or modifications mark no materialdeparture from the spirit and scope of the appended claims.

What I claim is:

1. A fork lift truck, comprising a vehicle body having a C-shaped groundplan providing an open side recess on one side of said body, a platformfor the body, a pivotal axle extending vertically upwardly from saidplatform and being fixedly secured thereto adjacent to an inner cornerof said body side recess, an outrigger supporting member slewablyjournaled on said pivotal axle and positioned above the top of said bodyplatform, a lazy tong mechanism defined by at least a pair of lazy tongshaving one end linked to said member and slewably supported therebyabove the top of said body platform, a frame linked to the other end ofsaid mechanism, a lifting mast member guided by said frame and beingvertically movable relative thereto, a lifting fork guided by and beingvertically movable relative to said lifting mast member, and said lazytong mechanism being horizontally etxendible at least so far that thepath of said vertically lifting mast member does not interfere with saidbody when the lazy tong mechanism is in a position parallel with thelongitudinal axis of said body, to allow lowering of said lifting mastmember to a position where its lowermost end substantially touches theroadway, said outrigger supporting member being slewable at leastthrough a angle whereby said lifting fork may be extended outselectively beyond the side of the truck or beyond the end of the truckand when said outrigger is slewed to a position wherein said forkextends endwise of the truck and is in retracted postion relative tosaid outrigger supporting member said lifting mast member may be loweredto rest said fork on said body platform for supporting a load thereonduring transportation thereof.

2. The fork lift truck as claimed in claim 1, in which said lazy tongmechanism is extendible so far that it can be swung around said pivotalaxle with the lifting mast member in its lowermost position at leastfrom a position parallel to the longitudinal axis of said body to aposition cross-wise to said longitudinal axis without said lifting mastmember interfering with said body.

References Cited UNITED STATES PATENTS D. 162,853 4/1951 Lull 214-670 X2,709,017 5/1955 Ulinski 214-730 3,259,257 7/1966 Brown et al. 214-6713,306,481 2/1967 Bowman-Shaw 214670 3,313,436 4/1967 Mathew et a1.214660 FOREIGN PATENTS 1,035,569 7/ 1958 Germany.

HUGO O. SCHULZ, Primary Examiner.

